Die bar or die bar attachment

ABSTRACT

The invention provides a die bar or a thimble-like tip attachment for a die bar of a type used for opening die sets. The die bar or attachment includes a roller (preferably nylon, or the equivalent) which enables the tool to roll along the die set.

173,228 2/1876 McKenna ..29/267UX Umted States Patent [151 3,680,838Dunn [451 Aug. 1, 1972 [54] DIE BAR OR DIE BAR ATTACHMENT 555,578 3/1896Marden 16/43 X 1 186 799 6/1916 Kistler ..2'54/13l 72] Inventor. L nn D.Dunn 1320 Peachtr e l v Line, Mount pm'spect, I. 60056 e 2,774,60912/1956 Winger ..l6/3O x 22 Fi May 8 1g70 FOREIGN PATENTS ORAPPLICATIONS 2 Appl NOJ 35 51 105,428 4/1917 Great Britain ..254/131Primary Examiner-Othe11 M. Simpson [52] US. Cl. ..',.254/l31, 29/239,29/267 A1 W i & whi l [51] Int. Cl. ..B66f 3/00 [58] .Field of Search..254/l20, 131; 29/239, 267; [57] ABSTRACT 249/205 18/2 2 The inventionprovides a die bar or a thi'mble-like tip attachment for a die bar of atype used for opening die sets. The die bar or attachment includes aroller [5-6] References cued (preferably nylon, or the equivalent) whichenables UNI STATES PATENTS the tool to roll along the dieset.'

9 Claims, 9 Dravving Figures PATENTEDAUB 1 1972 INVENTOR LYNN D DUNNMRQMW ATTORNEYS DIE BAR OR DIE BAR ATTACHMENT This invention relates todie bars and more particularly to die bars or attachments for die barswhich facilitate a manipulation of the die sets.

Those who are familiar with the tool and die makers tools will readilyrecognize the meaning of the term die bar. This is a tool used by a tooland die maker to pry apart mated parts of die sets. More particularly, adie bar looks somewhat like a crowbar with a sharp bend immediatelyafter the hook portion, thus giving a somewhat spoon shaped crosssection. The tip end of the die bar is placed against one side of a dieset and the bowl of the hook rests against the other side of the dieset. When the handle is manipulated, the top of the die set is workedfree of the bottom.

There are many difficulties which are encountered when die bars areused. Among other things, the tip of the bar mars the die-set, andthereafter the surface of the die set has an unacceptable appearancewhich tends to reflect adversely upon the tool makers competance. Toavoid such marring, the present practice is to coat the tip of the diebar with a soft metal, such as solder or a brazing material. However,this is a relatively expensive process since the solder wears offquickly and must be replaced often.

' There are a number of additional problems which either result from oroccur simultaneously with the use of die bars. For example, a tool anddie maker must assure a perfect alignment of die blocks as they aremounted in a die set. In part, he checks the alignment by listening forsqueaks or pings while he moves the die set from a closed to an' openposition. If the tip of the die bar scratches on the surface of the dieset, there is a noise which conceals and simulates any noise resultingfrom a mis-alignment. This noise adds to the time required to make thealignment. Also, it may even contribute to mis-alignments. Still anotherproblem results if the die bar cocks the die set while it is beingopened. Then instead of a smooth sliding action, there is a rubbingaction. Those who are skilled in this art will readily perceive stillother problems relating to the use of die bars.

In keeping with an aspect of the invention, these and other objects areaccomplished by providing a die bar or a thimble cap or attachment whichfits over the end of a die bar. More particularly, insofar as theattachment is concerned, the invention provides a metal or other blockhaving a cavity therein for receiving the end of the die bar. The otherend of the block has a roller which rolls against the upper part of thedie set to apply prying forces without marring the surface of the dieset. Preferably, the roller is a material, such as nylon. The advantagesof the nylon roller are first, that it is soft enough not to mar the dieset and second, it is elastic enough not to develop a flat surface whichwould prevent the rolling action.

The nature of the inventive die bar or thimble attachment will becomemore apparent from a study of the attached drawing, in which:

FIG. 1 is a perspective view of an inventive thimble attachment;

FIG. 2 is a side elevation view of the thimble attachment taken alongline 2-2 of FIG. 1;

FIG. 3 is a top plan view of the thimble attachment taken along line 3-3of FIG. 1;

FIG. 4 is a front elevation view of the thimble attachment taken alongthe line 4-4 of FIG. 2;

FIG. 5 is a bottom view of the thimble attachment taken along line 5-5of FIG. 4;

FIG. 6 is a side view of a die bar with a thimble attachment shownremoved from the tip end of the die bar;

FIG. 7 is a perspective view of a die set with a die bar having aninventive thimble thereon;

a FIG. 8 shows an alternative embodiment with the roller mounteddirectly on the tip end of the die bar; and

FIG. 9 is a perspective view which shows a ball bearing attached to theend of a hexagonal die bar 32b.

The inventive thimble attachment 10 comprises a body or block 11 havinga cavity 12 therein and a roller 13 mounted thereon. The block has apair of upstanding arms 14, 15 thereon, spaced apart by a distance whichis slightly more than the length of the roller 13. An axle 17 or a pairof trunnions rotatably support the roller so that it may turn freelyabout pivot points on the arms 14, 15. The cavity 12 has a cross sectionwith an inverted V-shape with contours and dimensions which conform toand complement the contours and dimensions on the tip end of the diebar. Thus, the block 10 fits thimble fashion over the end of a die bar.

There are a number of different ways to make the inventive thimbleattachment. For example, the block 11 could be a die casting. The arms14, 15 could be integral parts of plates 21, 22 which may be bolted orotherwise attached over the ends of the block 1 l.

Preferably the roller 13 is made of a tough, but slightly flexible,material such as nylon. If the roller is made of steel or other materialapproximately as hard as the die set, it would be possible to mar orscratch the surface of the die set. Also, if the material is relativelyunyielding, such as steel, flat surfaces might be formed on the roller,and it might notthereafter roll. Hence, a material such as nylon solvesmany problems. It is tough enough to withstand severe usage, it is softenough not to scratch, and it has an elasticity with a memory whichprevents any deformation.

FIG. 6 shows a die bar 29 having a handle 30, somewhat bowl shaped crook31, and a tip 32. The thimble attachment 10 fits snugly over the tip 32to form a single tool with roller 13 at the tip end. The roller 13 turnsabout an axis which is perpendicular to the handle 30.

FIG. 7 shows a die set with the die bar being used in the intendedmanner. More particularly, the die set comprises an upper or punchholder section 40 and a lower die set section 41 spaced and supportedwith respect to each other by any suitable number of leader pins. Thedrawing shows four such leader pins 42-45 which fit through bushings46-49. These bushings could also be ball bearing supports. When the dieset is closed, the two parts 40, 41 are separated by a shut height 50.

These two die set parts carry and support a pairof die blocks 54. As thepunch holder 40 moves up or down on the leader pins 42-45, the dieblocks move relative to each other. The alignment of these die blocksmust be perfect, or the tool and die operation will not be successful.Therefore, there is a need for slowly moving the punch holder 40 up anddown while making suitable adjustments at the bushings or bearings 4649associated with the leader pins 42-45.

To move the die set 40, 41 between its opened and closed positions, thedie bar 29 is placed within the shut height 50 between the upper orpunch holder section 40 and the lower section 41. The bowl 31 of the diebar rests on one die set section (the lower section 41), and the tipattachment l rests against the upper die set section 40. As the handle30 is pressed downwardly in the direction A, the die bar rocks on thebowl part 31, and the tip moves upwardly, in direction B.

During this upward movement, the roller 13 rolls freely along the lowersurface of the upper die set member 40. The nylon roller is very quietand can not be heard as it rolls along. No lateral forces can be createdin either of the directions C or D. A first advantage is that the diebar does not create any sounds. Any rubbing or scraping noise resultsfrom a misalignment of the die set. A second advantage is that it is notpossible to cock one half of the die set with respect to the other half.Those who are skilled in the art will readily perceive other advantagesof the invention.

It should be apparent that many alternative structures may be madewithout departing from the spirit and scope of the invention. In greaterdetail, FIG. 8 shows that the roller 13a may be attached directly to thetip end of the pry bar 32a, without requiring any attachment. The rolleris here shown as being attached to the end of the die bar by the plates21a, 22a. It should also be apparent that various sizes and shapes mayalso be adopted for either the thimble attachments or the die bars.Furthermore, other rolling means, such as a ball bearing 13b, may beattached to the end of the die bar, 32b, as shown in FIG. 9. Here thebearing 13b is shown as being held in place by an annular collar 60which is drawn down over the end of the die bar 32b by means of athreaded nut 61. By way of example, the tip end 32b of the die bar ishere shown as a hexagonal bar which is threaded at 62. Also, alternativebearings may support the roller trunnions.

Accordingly, the appended claims are to be construed as covering allequivalents falling within the true scope and spirit of the invention.

I claim:

1. A thimble-like attachment for the end of a die bar,

said attachment comprising a body having a V- shaped cavity therein,

said cavity having a contour and dimension which complements the contourand dimension of the tip end of said die bar, and

a rolling means on the end of said attachment.

2. The thimble-like attachment of claim 1 wherein said rolling means isa ball bearing.

3. The thimble-like attachment of claim 1 wherein said rolling means isa roller supported by saidbody on an axis which is perpendicular to theaxis'in which said die bar moves while it is working.

4. The thimble-like attachment of claim 3 and apair of end plates onopposite sides of said body for supporting trunnions formed on saidroller.

5. The thimble-like attachment of claim 4 wherein said roller is a nylonroller.

6. The thimble-like attachment of claim 3 wherein said roller is madefrom a tough material which is softer than steel and which has a memorythat prevents any d f ti 'iwi ne t ir n le l ike attachment of claim 3wherein the roller is close to the tip of the V of the cavity and itsaxis is at all points substantially in alignment with the center line ofthe V.

8. The combination of a die bar having an offset portion near one endwhich is V-shaped in cross section with a transversely extending tip,and a readily removable thimble-like attachment for that end,

said attachment comprising a body having a cavity therein,

said cavity having a contour and dimension which complements the contourand dimension of the tip end of said die bar, and

a rolling means on the end of said attachment.

9. The combination of a die bar having an offset portion near one endwhich is V-shaped in cross section with a transversely extending tip,and a readily removable thimble-like attachment for that end,

said attachment comprising a body having a cavity therein,

said cavity having a contour and dimension which complements the contourand dimension of the tip end of said die bar, and

a roller on the end of said attachment positioned close to said tip andapproximately aligned with the center of the V, and rotatable about anaxis parallel to said tip.

1. A thimble-like attachment for the end of a die bar, said attachmentcomprising a body having a V-shaped cavity therein, said cavity having acontour and dimension which complements the contour and dimension of thetip end of said die bar, and a rolling means on the end of saidattachment.
 2. The thimble-like attachment of claim 1 wherein saidrolling means is a ball bearing.
 3. The thimble-like attachment of claim1 wherein said rolling means is a roller supported by said body on anaxis which is perpendicular to the axis in which said die bar moveswhile it is working.
 4. The thimble-like attachment of claim 3 and apair of end plates on opposite sides of said body for supportingtrunnions formed on said roller.
 5. The thimble-like attachment of claim4 wherein said roller is a nylon roller.
 6. The thimble-like attachmentof claim 3 wherein said roller is made from a tough material which issofter than steel and which has a memory that prevents any normaldeformation.
 7. The thimble-like attachment of claim 3 wherein theroller is close to the tip of the V of the cavity and its axis is at allpoints substantially in alignment with the center line of the V.
 8. Thecombination of a die bar having an offset portion near one end which isV-shaped in cross section with a transversely extending tip, and areadily removable thimble-like attachment for that end, said attachmentcomprising a body having a cavity therein, said cavity having a contourand dimension which complements the contour and dimension of the tip endof said die bar, and a rolling means on the end of said attachment. 9.The combination of a die bar having an offset portion near one end whichis V-shaped in cross section with a transversely extending tip, and areadily removable thimble-like attachment for that end, said attachmentcomprising a body having a cavity therein, said cavity having a contourand dimension which complements the contour and dimension of the tip endof said die bar, and a roller on the end of said attachment positionedclose to said tip and approximately aligned with the center of the V,and rotatable aBout an axis parallel to said tip.